The Gut Microbiota Dysbiosis as a Trigger of Inflammation-Driving Pathogensis of Alzheimer’s Disease

Abstract

Alzheimer's disease (AD) is a degenerative disease of the central nervous system, and its pathogenesis is very complex. Gut microbiota is an immense and complicated microbial community that is regarded as the “second brain “by scientists. These microorganisms exist in the ecosystem of the gastrointestinal tract which is in the human body and form a relatively stable environment within the gastrointestinal tract. As a large number of microorganisms that can survive and coexist harmoniously in the human body, intestinal flora is a very important environmental factor and plays a very important role in the mutual transformation of people's health and diseases. On this basis, the cerebral intestinal axis is a two-way information regulation system that connects the brain and gastrointestinal functions. This means that intestinal microorganisms can participate in the brain-intestinal axis. Recent studies have shown that disturbances (compositional changes and translocations) of the gut microbiota are associated with neurological disorders (AD), where the gastrointestinal tract communicates with the central nervous system via the gut-brain axis, including direct effects on nerves, endocrine pathways, and immune regulation. Animal models, fecal microbiota transplantation, and probiotic interventions provide evidence for the association of gut microbiota with AD. The leaked bacterial metabolites may directly damage neuronal function, and may also induce neuroinflammation and promote the pathogenesis of AD. Therefore, the main goal of this review is to summarize, study and discuss the nowadays research and results of intestinal microbiota in Alzheimer-related mechanisms and to understand the relevance, function, and impact between the mechanism and Alzheimer’s disease.